Tube mill



cut out, or otherwise remove ?atented May 8, i923.

Ublllfifi @TATES hdddddl ELLIS C. SOPER, OF CHATTANOOG-A, TEENESSEE.

TUBE Minn Application filed August 15, 1918. Serial No. 249,960.

To all whom it may concern:

Be it known that I, ELLIS G. Sornn, a citizen of the United States, residing at Chattanooga, in the county of Hamilton and State of Tennessee, have invented certain new and useful Improvements in Tube Mills, of which the following is a specification.

My invention relates to a tube mill, and has for its object the, improvement of a device of this character.

In the operation of tube mills, the difliculty has been experienced, when moisture was present in the material which 'was being treated, that the vapor formed by the moisture causes the material to form a cake upon the sides of the cylinder and upon the surfaces of the wall, and if sufiicient moisture is present, the mill will eventually be plugged, and it then becomes necessary to the cake thus formed.

In accordance with my invention, the gases are evacuated from the tube mill chamber, and the difficulties above referred to are thereby avoided. My invention is particularly useful in grinding mixtures containing phosphate rock and sodium bi-sulphate known as nitre cake. The sulphuric acid from the nitre cake which is dissociated forms sulphuric anhydride and moisture, the latter frequently reacting with the rock to form the objectionable cake, when the process is carried out with a mill as ordinarily constructed. In accordance with my invention, the gases are evacuated from the tube chamber before they have an opportunity to react with the charge of material in the tube mill, and thereby the objectionable formation of cake is obviated.

My invention will best be understood by reference to the accompanying drawing, is a longitudinal section, partially in side elevation, of a device embodying one form of my invention.

Referring now to the drawings, A is a ball mill comprising a cylinder 10 closed at its ends by heads 10 and 10 which are provided with tr innions 11 journaled in bearings 12, which are in turn carried on the upper ends of standards 13 supported from a foundation which is indicated by the line 13 The cylinder 10 may be rotated by a suitable gear wheel 14 which is here shown as secured to one end of the cylinder. The materials to be treated are introduced to the cylinder through a suitable hopper 15, the

" the tube mill, and

lower end of which communicates with one end ofthe cylinder 10 by a pipe 16. The material is fed from the hopper 15 through the cylinder by means of a screw 17 which may be rotated by a pulley 18. The cylinder 10 is indicated as of the type in which two chambers 19 and 20 are provided with a partition which I have indicated in general, by the reference numeral 13 The chamber 19 is provided with balls 21, and the chamber 20 with balls 22, which are preferably of a less diameter than those of the chamber 19. It will, of course, be understood that the equivalent of balls such as cylinders, for example, may be used. Thepartition B comprises two plates 23 and 24, the plate 23 being provided with openings 25 through which the material from the chamber 19 passes to the space between the plates 23 and 24, while the plate 24 is provided with a central opening 26 through which the material in the space between the two plates is discharged into the chamber 20. The plate 23 is preferably provided with a conical member 27 facing the opening 26 in the plate 24:, in order to direct the mater1al between the two plates to the opening 26. The outlet end of the cylinder 10 is preferably provided with a transverse plate 28 provided with openings 29 through which the ground material passes into the space between the plate and the head of the cylinder. The plate 28 is preferably rovided with a conical member 30 disposed on the central portion of its outer face and opposite. an opening 31 within the trunnion 11 at the outlet end of the cylinder, for the purpose of directing the treated material to said opening.

So much of the tube mill as has hitherto been described is old in the art, and no novelty is claimed for the same per se.

In accordance with my invention, provision ismade for assing a current of air through the tube null for the purpose of removing therefrom any moisture or other deleterious gases or vapors that may be present. For this purpose an air-tight receptacle 32 is disposed at the outlet end of forms therewith an airtight joint. A. tube 33, preferably directed upwardly, communicates with the receptacle 32. In order to create an upward draft in the tube 33, and suction in the tube 10, a pipe 34 is provided which communicates with a source of fluid pressure (not shown),

, from the upper end and which is provided with a valve 35. The free end of the tube3t passes through the wall of the tube 33, and its inner end is bent upwardly, as at 36, in order to impart an ejector action to the gases within'the tube 33.- It will be understood that the valve 35 furnishes a ready means of controlling the amount of air that is introduced to the tube 33, in order to take careof different degrees of moisture that may be present in the treated material. The upper end of the tube 33 opens into a receptacle 37 within which the dust which is carried over from the tube mill is separated from the gases in which it is carried. A hood 38 is disposed above the free end of the tube 33 and may be attached to the wall of the collector or receptacle 37 by a bracket '39. The dust in the gases issuing of the pipe 33, are separated from the ases by means of the hood 38 and directed downwardly towards the sloping lower-sides 40 of the receptacle 37. The gases are released from the receptacle 37 by means of a vent pipe 41. The treated material issuing from the tube mill, is received in the receptacle 32 and passes downwardl into a suitable chute 42, the lower end 0 which is provided with a valve 43 for controlling the discharge of material from the chute, and normally maintaining the lower end of the same air-tight. A tube at is connected to the lower tapering end of the receptacle 37 and communicates with the chute 42, thus dischargin the dust which is collected in the reoeptac e '37 into the main body of material which is discharged from the tube mill.

What I claim and desire to secure by Letters Patent of the United States is 1. In combination, a pulverizing machine having a main discharge for the pulverized material, means for creating a flow of air through the machine and for evacuating the air and moisture therefrom to the atmosphere independently of the pulverized material and comprising a separating chamber in which dust is separated from the air, and means tordeliverin the separated dust to the main discharge em the mill.

2. In combination, a pulverizing machine having a discharge for the pulverized mate rial, means for creating a flow of air through the machine and for evacuating the air and moisture therefrom separately from the ulverized material discharged from the machine, a separating chamber for separating dust from the air and into which the evacuated air is led, means for delivering the separated dust from said chamber to the main body of the material discharged from the machine, and means for delivering the air from said separating chamber to the at mosphere.

3. Th combination, a pulverizing machine, a main discharge for the pulverizing mate rial, means for withdrawing vapors and gases from the machine, means for separating dust from the vapors and gases so withdrawn, means for discharging the vapors and gases to the atmosphere and means for delivering the. separated dust to the main discharge.

lln testimony whereof l have hereunto signed my name in the presence of two subscribing witnesses.

ELLIS C. SQPER.

Witnessm:

F. J. MORGAN,

J. T. Lama 

